Initial workpeice tooling set-up instructions using a pendant controller type machine

[Nthkentman]

Thanks Jazz for the advice.

I set a 19mm sacrificial board on the machine today and on top of that I set a small 200 x 120 x 13mm thick piece of ply

After setting the machine to "HOME, I then, using my procedure above, brought the arm axis's to the centre of my workpeice. Positioned the cutter to the correct marked centre and zero'd X & Y.

Then I brought the head down and jogged until the cutter (A 3mm dia single flute end mill) just touched the surface and zero'd Z

In my V Carve software I set the XY to centre of the work, and the height of the material as 13mm. Reference start for Z axis was top of workpiece at centre.

When I started the machine and set it all in motion the X & Y axis travelled to the exact set point in the middle of my piece as expected, but the Z rapid plunged into that point to the collet nut depth ! (Until I hit the E Stop button)

What did I do wrong? I'm missing something here and feel a little dumb.... Newbie cock up I know... Loooong time since I did this and it's a fun learning curve again

[Clive S]

By default V carve sets the material z position to the bottom of the job. Did you change it to the top?
Also did you have the "model in material" set to "gap above model". .. Clive

[Nthkentman]

By default V carve sets the material z position to the bottom of the job. Did you change it to the top? Clive

Hi Clive, yes I did change it to the top. The diagram shows as you say the default at the bottom of the workpiece, (Which I also tried) but irrespective of how I set it the Z axis is wrong... I'm wondering now if I am sending the wrong G code to the machine.
The PP asks for a file with extension .nc
So I use the first available .nc choice as my machine is not listed.
Perhaps I'm doing that wrong ?

[Clive S]

Well if you want to be sure have a look at the gcode it produced you can open the file by renaming it to .txt ..Clive

[Nthkentman]

Thanks Clive, I may try that and post the results here. I'm fairly new to G code, as when I were t'prentice the programming and such was done by the clever office bods :-)

How would I detect if the code is wrong please?

[Clive S]

If you post the top 20 line of code it should be easy to see. you just look for the g1 z!!! parts. Did you re read my edited post lower down for the position of the model in material. ..Clive

[Nthkentman]

I'll got to my machine tomorrow and get the file. I'm not sure what you mean about the position of the model in the material though. Sorry if this seems a bit dumb, but I did think I could remember more ... Maybe not

[JAZZCNC]

What did I do wrong? I'm missing something here and feel a little dumb.... Newbie cock up I know... Loooong time since I did this and it's a fun learning curve again

Don't feel dumb we have all been here in some form or another.! . . My first attempt with G-code ended thumping a perfect square hole thru 40mm of MDF after sending Z axis wrong way. . .Lol

I don't use V carve but If it's not that you have set the Zero point at bottom of material and you can't find any obvious reason then it could be the Control as a TOOL offset set.
Just like WORK OFFSETs you can have TOOL OFFSET's so your control could have TOOL OFFSET's entered into it.?
So when your G-code calls for first tool it applies the OFFSET set in the control. This could give the trouble your seeing.

If you open the G-code file you look for G43 H# with the number being the tool number probably 1 in this case. It will be some where near the top and probably will be near the tool number IE:
T1
G43 H1

If so then chances are you have TOOL OFFSET applied. Just remove the G43 H1 or put G49 straight after it.

[Nthkentman]

Thanks Jazz, I actually believe it's me getting it wrong tho... I only have the facility for XY offset in V Carve,
I wonder if plain G Code in txt will work, even though the PP program suggests .nc extension... Not sure why there is a difference....
Looks like I'll be installing Mach3 and getting someone clever in to convert the machine board otherwise

[JAZZCNC]

Thanks Jazz, I actually believe it's me getting it wrong tho... I only have the facility for XY offset in V Carve,

It will allow tool offset's I'm sure of it. Not much good if it doesn't as many machines need tool offsets to work correctly, esp with toolchangers.

I wonder if plain G Code in txt will work, even though the PP program suggests .nc extension... Not sure why there is a difference....
Looks like I'll be installing Mach3 and getting someone clever in to convert the machine board otherwise

The file .nc extension will open in notepad. When you click it to open and get the message saying choose software to open with then use notepad and save as default for this file type.

If you create file in note pad then just replace .txt with .nc and it will work. Both are just plain txt files the .nc extension is nothing special it's just the DSP will be looking for .Nc extension. Chances are it will use .txt as well and just defaults to .nc.?